Method for rapid prototyping by using linear light as sources

ABSTRACT

A method for rapid prototyping by using linear light as sources employs DLP (Radiation Hardening Formation) or LCD, together with the portable devices and linear light source to treat the raw material in two stages. The first stage is to spread the raw material to a selected zone by nozzles or rollers and illuminating the material to let the material being processed and have physical o mechanical changes. The second stage is to use more powerful linear light source with the cooperation of the portable DMD (Digital Micromirror Device) or LCD (Liquid Crystal Display) to illuminate the material to make it have a second times of physical o mechanical changes. By the piling up the layers of the material, a complete 3-D work piece is obtained.

FIELD OF THE INVENTION

The present invention relates to a method for rapid prototyping by usinglinear light as sources and piling layers of 2-D images to be a 3-Dimage.

BACKGROUND OF THE INVENTION

Typically, a complete process for developing a new product from design,making a prototype, management of production processes, mass productionto introducing the product to the market, there always need a prototypefor evaluation and examination. Thus, a prototype that is easilymanufactured and amended is an important factor for a successfulproduct. How to manufacture the prototype that meets needs is crucialfor not spending too much manufacturing cost.

There are numerous methods available for prototype production such asthe conventional manual production, CNC milling and carving machine. Asfor the conventional manual model production, except for experiences, itlacks precision. The CNC milling or carving machine are also confined tothe types of chucks, bits or the size of the machine.

With the improvement in technologies, the quick growth of CAD packagesoftware has distinguishably shortened the development cycle for newproducts. For the past few years, the industry of Rapid Prototyping haswell integrated with the CAD and production technologies and remarkablyimproves the efficiency for product design. The methods of quickformation can be classified as Layer Manufacturing, AutomatedFabrication, Freeform Fabrication and Solid Imaging, etc. For thecontinuous development of past decades, there are ten more types of RPmodels available in the current markets. The methods of rapid formationcan, according to the use of energy resources, be classified as LightIlluminating Processing, Stick-Formation processing and ComplexFormation Processing. According to the documentary records, we classifythe production process for rapid prototype making in terms of work pieceproperties, energy resources types, and stacking types. As shown in FIG.1, some conventional production processes are as follows:

1. SLA (Radiation Hardening Formation): It is currently the most widelyapplied processing method with the formation by means ofStereolithography Formation. This production process is designed withHe—Cd or Ar+ ultraviolet laser galvanometer-mirror to scan andilluminate the fluid polymers (light hardening resins). The resinrequired for formation becomes a thin film (around 0.15 mm˜0.05 mm).Then, with the descending of Z-axis, the work piece zone is coated witha layer of liquid polymers. By using a scraper to destroy the surfacetension of the liquid polymers a flat surface is obtained. The liquidpolymer is then scanned by laser beams so that the layers are combinedfirmly. A 3-D solid work piece is obtained by repeating the previoussteps. The flow chart of SLA (Radiation Hardening Formation) is shown inFIG. 2.

A U.S. Patent owned by 3D Systems, USA, filed on Aug. 8, 1984, issued onMar. 11, 1986. The patent application dominates most of the market.

The shortcomings of the SLA are:

a. establishing support;

b. because of liquid resins, the material buckets must be completelyfilled so that the material cost will be high.

2. SLS: illuminating the hi-molecule resin powders by hi-power laser tosinter and the resins are melted and affix to the work pieces to form athin layer. After that, the Z-axis of the machine descends and a newlayer of powder is spread on the work piece by using a scraper. Theouter layer is then sintered by the laser beams. By repeating theprocedures, an overall 3-D solid work piece is obtained. The SLS flowchart is shown in FIG. 3.

The typical problems of the SLS are:

a. the powder cannot be spread evenly by using rollers or scrapers;

b. the powder needs a long period of time to be warmed which prolongsthe working hours;

c. the powder easily causes flaying dust and potentially harmful tohuman health.

d. the powder is difficult to be heated evenly;

e. unavailable for the production of large work pieces.

3. FDM: the powder of work piece is pre-mixed with binder to formelongate stripes, the stripes are heated and melted and using nozzles tofeed for production. The main defect of this method is that the surfaceof work piece is rough and requires support. The flow chart is shown inFIG. 4.

4. 3DP: it is also known as 3-D printing. This method establish a thinlayer of powder and selectively sprays adhesive on the surface of powderby method of jetting such that the powder is affixed and form a thinlayer on solid work pieces. By repeating the procedures, we can finishthe production of 3-D solid work piece. The flow chart (shown as FIG. 5)of 3DP includes the problems as below:

a. Due to the formation is fully depended upon nozzles, the precision ofnozzles is high.

b. It will come with inferior precision.

c. The materials of work pieces can only be porous items.

d. The powder cannot be spread with uniform densities.

5. LOM: The already-solidified thin layers are cut to somecross-sectional slices by laser and the layers are connected by binder.By this method, the molecules within the material layers are welllinked. Before production, each layer of material must be preparedindividually, resulting in complex operation procedures. Furthermore,the largest defect of this process is that the removal of residematerials is quite difficult.

6. OBJet: OBJet is also a type of 3-D printing process. The OBJet isdesigned with 2 different types of materials. One type of the materialsis the material to create the 3-D solid work pieces and the other typeof material is used as support for the models of work pieces. With theOBJet method, the nozzles are filled with two different types ofmaterials and then use the ultraviolet radiation to make maturity of thematerials of work pieces and the strength will be also enhanced. Thematerials used as support finally becomes gel type substance. Byrepeating the foresaid procedures, we can finish the a 3-D solid workpiece.

The OBJet production process is featured with the advantages like highquality, high precision, cleansing and speedy operation. However, withinthe production process, the most important component is the nozzle. Ifthe nozzle control is inferior, the precision of finished products willbe much more defective. The nozzle of high precision is quite expensivebut results in frequent congestion and this situation will significantlyaffect to cause much production cost.

7. The conventional DLP (Radiation Hardening Formation): DLP is also atype of stereolithography process and the differences compared with SLAare that the SLA is meant to harden the resin by use of a laser. Becausethe laser beams are thin and liner laser beams, thus, it will prolongthe production process. Also, the cost for using a laser as ignitionresource is high. DLP (Radiation Hardening Formation) is radiated withthe light radiated from halides and it is further controlled by DMD(Digital Micromirror Device) for the hardening radiation directly ontothe resins. Because the light sources of DLP are able to illuminate acertain zone, it can significantly shorten the working hours. The DLPproduction process is controlled by DMD for precise processing.Currently, the resolution can reach 1280*1024; namely, the commondifference can be reduced within+/−0.005 inch.

The DLP uses a single material. When the product is formed by means ofDLP, the material is hardened by light illuminating. As the workingplatform is descended, the hardened materials is covered by a layer ofunhardened materials. By repeating the foresaid procedures, we canfinish a 3-D solid work piece. The major problems happening to DLP are:

1. Because of the preparation for fluid materials, the material bucketfor work piece must be completely filled. Thus, it causes high materialconsumption and cost.

2. The precision is entirely controlled by DMD. Thus, the high precisionof DMD is extremely required so that it will directly cause higherproduction cost.

3. The process is thoroughly triggered by light sources so that lightisolation becomes critically important. Also, the DMD is available forprovision of low density light and it is quite sensitive to the ambientlight sources. Thus, the material buckets are also vulnerable for lightreaction to cause the increasing difficulty for material storage.

4. When creating some work pieces, additional supports are required.

5. Due to the large illumination area, if the intensity of light sourcesis not high enough, the material cannot react as desired.

The processing flow chart of DLP is shown in FIG. 6 to 8.

Beside the seven types of technologies, hereby, another Rapid PrototypeMethods proposed by Hwahsing Tang is introduced in 2001. This method isespecially meant for the creation of 3-D ceramic work pieces. Firstly,the inorganic binder and dissolving agent will be added into the ceramicpowder. These materials will be formed into a composite with plasticity.Thereafter, the composite will be placed with a thin layer and the layeris subsequently heated to harden the materials. At this moment, due tothe moisture decrement of inorganic binders when it is hardened to causehigher density and affixation, it will result in slightly inferiorintensity. As for the substance property, it acts like the dried slurfrom the sintered ceramic materials. Following that, laser beams areused to sinter the selected zone for the secondary hardening process. Atthis moment, the hardening is well affixed by the sintering of ceramicpowder. The strength is far beyond the hardened parts merely throughdehydration. Thus, the inventor can select an adequate method toseparate the substances from the materials with two hardness degrees.However, this production process is mainly applied to the production ofceramic work pieces to perform the relevant ceramic slur technologies.It is actually not suitable for the rapid prototyping general workpieces.

SUMMARY OF THE INVENTION

The present invention relates to a method for rapid prototyping by usinglinear light as sources. The method divides a 3-D image designed by CADinto a plurality of 2-D areas which are overlapped onto each other toform the 3-D image. The method comprises the following steps:

(1) putting raw material onto a defined zone;

(2) illuminating the raw materials a first time to cause a firstphysical or chemical change therein, so as to make the raw material intoa gel-form substance;

(3) using more powerful linear light source with cooperation of aportable Digital Micromirror Device (DMD) to scan the selected zones ofthe material to cause a 2nd physical or chemical change thereto;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images; and

(5) removing the material with the first change from the material with2nd change so as to obtain a solid work piece.

The present invention will become more obvious from the followingdescription when taken in connection with the accompanying drawingswhich show, for purposes of illustration only, a preferred embodiment inaccordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the classification of rapid prototyping;

FIG. 2 is a flow chart of SLA;

FIG. 3 is a flow chart of SLS;

FIG. 4 is a flow chart of FDM;

FIG. 5 is a flow chart of 3DP;

FIG. 6 is a flow chart of Type 1 of DLP;

FIG. 7 is a flow chart of Type 2 of DLP;

FIG. 8 is a flow chart of Type 3 of DLP;

FIG. 9 is a flow chart of the method of rapid prototyping of the presentinvention;

FIG. 10 is a flow chart of the first embodiment of the method of rapidprototyping of the present invention;

FIG. 11 is a flow chart of the second embodiment of the method of rapidprototyping of the present invention;

FIG. 12 is a flow chart of the third embodiment of the method of rapidprototyping of the present invention;

FIG. 13 is a flow chart of the fourth embodiment of the method of rapidprototyping of the present invention;

FIG. 14 is a flow chart of the fifth embodiment of the method of rapidprototyping of the present invention;

FIG. 15 is a flow chart of the six embodiment of the method of rapidprototyping of the present invention;

FIG. 16 is a flow chart of the seventh embodiment of the method of rapidprototyping of the present invention;

FIG. 17 is a flow chart of the eighth embodiment of the method of rapidprototyping of the present invention; and

FIG. 18 is a flow chart of the ninth embodiment of the method of rapidprototyping of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 9, the method for rapid prototyping of the presentinvention comprises the following steps:

(1) preparing raw material onto a defined zone by using rolling, nozzlesspreading, or by spreading the raw material and then rolling to obtainan even and thin layer of material with flat surface;

(2) illuminating the raw materials by light source, electronic beams, orheating to cause a first time of physical or chemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) to scan the selected zones of thematerial to cause a second time of physical or chemical changes;

(4) repeating pre-set times of the step (1) to (3) and removing thematerial without the second time of change by proper methods so as toobtain a solid work piece.

As shown in FIG. 10, the first embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) rolling raw material onto a defined zone;

(2) illuminating the raw materials cause a first time of physical orchemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) to scan the selected zones of thematerial to cause a second time of physical or chemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 11, the second embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) rolling raw material onto a defined zone;

(2) illuminating the raw materials by electronic beams to cause a firsttime of physical or chemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) to scan the selected zones of thematerial to cause a second time of physical or chemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 12, the third embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) rolling raw material onto a defined zone;

(2) heating the raw materials to cause a first time of physical orchemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) to scan the selected zones of thematerial to cause a second time of physical or chemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 13, the fourth embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles;

(2) illuminating the raw materials to cause a first time of physical orchemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 14, the fifth embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles;

(2) illuminatin the raw materials by electronic beams to cause a firsttime of physical or chemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 15, the sixth embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles;

(2) heating the raw materials to cause a first time of physical orchemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 16, the seventh embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles and rollingthe material to have a flat surface;

(2) illuminatin the raw materials by electronic beams to cause a firsttime of physical or chemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 17, the eighth embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles and rollingthe material to have a flat surface;

(2) illuminatin the raw materials by electronic beams to cause a firsttime of physical or chemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

As shown in FIG. 18, the ninth embodiment of the method of rapidprototyping of the present invention includes the following steps;

(1) spreading raw material onto a defined zone by nozzles and rollingthe material to have a flat surface;

(2) heating the raw materials to cause a first time of physical orchemical changes;

(3) using more powerful linear light source with cooperation of portableDigital Micromirror Device (DMD) or Liquid Crystal Display (LCD) to scanthe selected zones of the material to cause a second time of physical orchemical changes;

(4) repeating pre-set times of the step (1) to (3) and establishingconnection between layers of the 2-D images;

(5) removing the raw material from the object with the second time ofchange so as to obtain a solid work piece.

The material experienced two times of physical and chemical changes soas to have stronger mechanical features. In this method of the presentinvention, the material with weaker feature is supported by the materialhaving stronger features and the two types of materials can be separatedby proper methods. Therefore, the 3-D object can be obtained within ashort period of time.

While we have shown and described the embodiment in accordance with thepresent invention, it should be clear to those skilled in the art thatfurther embodiments may be made without departing from the scope of thepresent invention.

1. A method for rapid prototyping by using linear light as sources, themethod comprising the following steps: (1) dividing a 3-D image into aplurality of 2-D images which when overlapped reproduce the 3-D image;(2) depositing a layer of a raw material onto a defined zone; (3)irradiating the deposited layer of the raw material with a first energysource to convert the entire raw material layer into a gel-formsubstance layer; (4) irradiating selected portions of the gel-formsubstance layer with a second energy source to solidify the irradiatedportions of the gel-form substance layer, the second energy source beinga linear light source, the selected portions of the gel-form substancelayer being scanned in correspondence to a respective one of theplurality of 2-D images; (5) repeating steps (2) to (4) until each ofthe plurality of 2-D images have been scanned and establishingconnection between each of the layers corresponding to the plurality of2-D images; and (6) removing the gel-form material substance layerportions from the solidified portions to obtain a solid work piece. 2.The method as claimed in claim 1, wherein the step of depositingincludes the step of spraying the raw material into the defined zoneusing nozzles.
 3. The method as claimed in claim 2, wherein the step ofspraying is followed by the step of rolling the sprayed layer of rawmaterial.
 4. The method as claimed in claim 1, wherein the raw materialin step (3) is irradiated using electronic beams.
 5. The method asclaimed in claim 1, wherein the step of irradiating selected portions ofthe gel-form substance layer includes the step of scanning the selectedportions of the gel-form substance layer using portable Liquid CrystalDisplay (LCD).
 6. The method as claimed in claim 1, wherein the step ofirradiating selected portions of the gel-form substance layer includesthe step of scanning the selected portions of the gel-form substancelayer using a portable Digital Micromirror Device (DMD).